1. Technical Field of the Invention
This invention relates to a thermosyphonic method for reacting propylene with tertiary butyl hydroperoxide in solution in tertiary butyl alcohol in the presence of a catalyst to form propylene oxide and additional tertiary butyl alcohol and by-products and to a thermosyphonic reactor useful for the process.
2. Prior Art
It is known to react olefins such as propylene with hydroperoxides such as tertiary butyl hydroperoxide in liquid phase in the presence of a molybdenum catalyst as shown, for example, by Kollar U.S. Pat. No. 3,351,635. See also Kollar U.S. Pat. No. 3,947,500 disclosing the reaction of a hydroperoxide such as, for example, alpha phenyl ethyl hydroperoxide in solution in ethyl benzene with propylene in the presence of a soluble molybdenum naphthenate catalyst.
Marquis et al. U.S. Pat. No. 4,626,596 discloses a method for the preparation of soluble molybdenum/alkylene glycol catalyst and their use in catalyzing the reaction of propylene with tertiary butyl hydroperoxide to provide propylene oxide in additional tertiary butyl alcohol in solution in a solvent such as tertiary butyl alcohol. See also Marquis et al. U.S. Pat. No. 4,650,886.
The reaction is highly exothermic and involves the use of a hydroperoxide which, under adverse conditions is potentially explosive. Therefore, careful control of temperature and the reaction conditions is necessary.
It is also known to conduct gas-liquid chemical reactions in "closed loop" reactors as disclosed, for example, in Papp et al. U.S. Pat. No. 4,312,837 which discloses the use of a closed loop reactor comprising an ascending vertical tube and a descending vertical tube for the reaction of synthesis gas with an olefin in the presence of a catalyst. A reaction of this nature is also known as an Oxo synthesis.
Other references showing closed loop gas-liquid chemical reactors include Westerlund U.S. Pat. No. 3,502,443 which discloses a reactor useful for chlorine dioxide generation, Schuster et al. U.S. Pat. No. 4,482,692 which discloses a gas-liquid reaction conducted in a closed loop such as an oxygenation reaction. Other reactors are shown in Prave et al. U.S. Pat. Nos. 4,545,945 and 4,683,122 wherein a gas and a liquid are brought into contact in a dual zone reactor having an upflow portion and a downflow portion.
Vernon U.S. Pat. No. 3,212,860 discloses a process wherein two immiscible liquid chemicals are reacted in an upstanding reactor having a downflow portion and an upflow portion, such as an alkylation reaction wherein an olefin and isobutane are reacted.